Cellular technology has evolved over the past decade. For example, with the evolution of Third Generation Mobile Systems towards High-Speed Downlink Packet Access (HSDPA) in Release 5 and High-Speed Uplink Packet Access (HSUPA) in Release 6, higher data rates may be obtained. This has opened the door to new mobile devices that offer constant connectivity to the Internet, while continuing to offer good quality voice services. The desire to maintain connectivity to virtual communities and the Internet, in conjunction to the arrival of new devices capable of offering a satisfying user experience has increased the demand on the existing network infrastructures.
To satisfy this increasing demand, network operators have deployed new infrastructure and/or acquired additional spectrum. One strategy that is also being used to satisfy the increase in traffic is to deploy smaller cells, also referred to as femto or pico cells, in areas where the demand is higher. These femto cells are typically located under the umbrella of a larger macro cell and while they do not extend the coverage they increase the available throughput in buildings and other public areas such as subways stations, coffee shops, shopping malls and so on.
Femto cell NodeBs (i.e., NodeBs, eNB, base stations (or base nodes), access points, and the like) have the advantage of being low-cost and small when compared to typical macro cells NodeBs. However, they typically serve a smaller number of user equipment (UE) or wireless transmit/receive units (WTRUs) and are thus not very power-efficient compared to a macro cell NodeB.
The NodeBs in a typical wireless network (for macro or femto cells) may consume a large amount of energy. While a portion of the energy consumed is used to carry data information, a large portion of that energy is also used on overhead control channels. Also, cellular networks may include devices such as base stations and wireless transmit/receive devices (WTRU), for example, that may consume more power than necessary for the respective operations and functions that the devices may implement at any particular time or in particular periods of time.